Where to write a file in Tomcat 8 and Servlet /JSP on my Hard Disk ?

I want to write my.properties file. My query is that “In which path should it be created”. I have installed glassfish on my Linux 14.04 machine on this path: /opt/glassfish4 and created the file my.properties at: /opt/glassfish4/glassfish/domains/swManzana/config/my.properties

While executing the above code my.properties file not created. Why Tomcat is not creating this file. I have properly checked my tomcat installation and found no issues in access web Pages and ports. Can anyone suggest me some knowledgeable tutorials URL Links on Java questions and answers, so that I can get my query resolved faster.